Portable beverage dispensing system

ABSTRACT

A portable beverage dispensing system includes a supply of flat water and a supply of pressurized gaseous carbon dioxide. A first motorless carbonator is configured to receive a portion of the flat water and a portion of the carbon dioxide and to cause a portion of the carbon dioxide to dissolve in the flat water to produce partially carbonated soda. A second motorless carbonator is configured to receive a portion of the partially carbonated soda and a portion of the carbon dioxide and to cause a portion of the carbon dioxide to dissolve in the partially carbonated soda and to produce fully carbonated soda. The system also includes a dispenser for selectively dispensing the fully carbonated soda.

TECHNICAL FIELD

The invention generally relates to post-mix beverage dispensing systems,and more particularly relates to a compact and portable post-mixbeverage dispensing system suitable for use on airplanes, railcars, orother applications where space and/or facilities are limited.

BACKGROUND

Post-mix beverage dispensing systems provide a convenient and efficientmeans for dispensing carbonated beverages to consumers. Such systemsproduce carbonated water, and mix flavored syrups with the carbonatedwater in desired ratios at a dispensing head or bar gun. Where suchsystems can be used, post-mixed beverages are highly cost-effectivecompared to more expensive pre-packaged carbonated beverages such ascanned or bottled soft drinks.

Presently, commercial airlines typically serve prepackaged beverages totheir passengers. Prepackaged beverages such as canned beverages arestored at room temperature in a portable cart that is sufficientlynarrow to pass down the aisles of most commercial aircraft. Aspassengers request carbonated beverages, flight attendants remove theselected canned beverages from the portable cart, and pour the beveragesover ice in a glass or cup. This process is time-consuming, and can bedifficult or impossible under turbulent flight conditions. On shortflights, at least some passengers often are unable to obtain a beveragedue to the time required to dispense canned beverages to previouslyserved passengers. In addition, the cost per serving of canned beveragesis considerably higher than the cost per serving cost post-mixedcarbonated beverages. Serving pre-packaged beverages also generatesconsiderable waste such as empty beverage cans that must be handled,temporarily stored, and discarded. In addition, pre-packaged carbonatedbeverages have a limited shelf life.

The challenges associated with producing compact and portable post-mixbeverage dispensing systems are numerous. Such systems must operatewithout external sources of water and electric power. In addition, suchsystems must be sufficiently compact to permit their use in limitedspaces such as the narrow confines of airplanes. Because such systemsnecessarily include stored high pressure carbon dioxide gas, the systemsalso must comply with stringent government safety regulations governingthe packaging and transportation of high pressure gas containers.Furthermore, the makers of the most popular carbonated beverages (e.g.Coke ® and Pepsi ®, require their products to be consistently dispensedaccording to exacting product standards. One such requirement is thatthe dispensed beverages have a commercially acceptable level ofcarbonation of about 3 percent to about 4 percent.

Others have attempted to produce compact and portable post-mix beveragedispensing systems with limited success. For example, U.S. Pat. Nos.5,411,179 and 5,553,749 to Oyler et al. describe self-contained beveragedispensing systems that use a single low-pressure motorless carbonatorto carbonate flat water to produce soda for use in post-mixing anddispensing carbonated beverages. Unfortunately, such low-pressuremotorless carbonators produce soda having only about 2.5 percentcarbonation, which is well below a commercially acceptable level ofcarbonation and/or product standards dictated by makers of Coke ® andPepsi®. Others have tried to address this problem by developing portablebeverage dispensers that include a single high-pressure motorlesscarbonator. The term “high pressure motorless carbonator” as used hereinrefers to a motorless carbonator that operates at an internal pressureof at least about 100 psi. For example, U.S. Pat. No. 6,021,922, U.S.Pat No. 6,234,349, and U.S. Pat. No. 6,253,960 to Bilskie et al.describe self-contained high-pressure beverage dispensing systems thatinclude a single motorless carbonator that operates at a gas pressure ofbetween 90-110 psi. Unfortunately, these systems also do not provide ahighly portable and compact beverage dispensing system that producessoda that consistently meets commercially acceptable levels ofcarbonation and complies with applicable federal safety regulations foruse on commercial aircraft.

Accordingly, there is a need for an effective, compact, and highlyportable beverage dispensing system that operates without externalsources of water and electric power. In addition, there is a need forsuch a system that is sufficiently compact to permit its use in limitedspaces such as the narrow aisles of airplanes and passenger railcars.Such a system also must comply with applicable government safetyregulations, and must consistently supply a commercially acceptablelevel of carbonation.

SUMMARY

A portable beverage dispensing system includes a supply of flat waterand a supply of pressurized gaseous carbon dioxide. A first motorlesscarbonator is configured to receive a portion of the flat water and aportion of the carbon dioxide and to cause a portion of the carbondioxide to dissolve in the flat water to produce partially carbonatedsoda. A second motorless carbonator is configured to receive a portionof the partially carbonated soda and a portion of the carbon dioxide andto cause a portion of the carbon dioxide to dissolve in the partiallycarbonated soda and to produce fully carbonated soda. The system alsoincludes a dispenser for selectively dispensing the fully carbonatedsoda.

A portable beverage dispensing module includes a housing and a cylinderin the housing containing pressurized carbon dioxide. A first motorlesscarbonator is located in the housing, and is configured to receive flatwater from a flat water supply and to receive a portion of the carbondioxide. The first carbonator causes a portion of the carbon dioxide todissolve in the flat water to produce partially carbonated soda. Asecond motorless carbonator is also located in the housing. The secondcarbonator is configured to receive the partially carbonated soda and aportion of the carbon dioxide, to cause a portion of the carbon dioxideto dissolve in the partially carbonated soda, and to produce fullycarbonated soda. At least one pneumatic pump powered by the pressurizedcarbon dioxide is configured to pump flat water from the flat watersupply to the first carbonator. The module further includes a dispenserfor selectively dispensing the fully carbonated soda.

A high pressure gas cylinder for a portable beverage dispensing systemincludes a neck having a throat. A piercable membrane seals the throatof the cylinder. The term “high pressure gas cylinder” as used hereinrefers to cylinder that is capable of safely storing compressed gas at apressure of at least about 1800 psi.

A two-stage motorless carbonator includes a first carbonation chamberhaving a flat water inlet, a first carbon dioxide inlet, and a firstsoda outlet. A second carbonation chamber includes a soda inlet, asecond carbon dioxide inlet, and a second soda outlet. A conduitconnects the first soda outlet of the first carbonation chamber to thesoda inlet of the second carbonation chamber. Partially carbonated sodafrom the first carbonation chamber is passed to the second carbonationchamber through the conduit and is further carbonated in the secondcarbonation chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an embodiment of a beverage dispensingsystem according to the invention;

FIG. 2 is a perspective view showing the front of an embodiment of abeverage dispensing module for use in the beverage dispensing system ofFIG. 1;

FIG. 3 is a front elevation view of the beverage dispensing module ofFIG. 2;

FIG. 4 is a rear elevation view of the beverage dispensing system ofFIGS. 2 and 3;

FIG. 5 is a perspective view showing the rear of the beverage dispensingmodule of FIGS. 2-4;

FIG. 6 is a perspective view of a high-pressure carbon-dioxide cylinderfor use in the beverage dispensing module shown in FIGS. 2-5;

FIG. 7 is a cross-sectional view of the high-pressure carbon dioxidecylinder of FIG. 6;

FIG. 8 is a detailed perspective view of the neck end of the cylindershown in FIGS. 6 and 7;

FIG. 9 is a detailed perspective view of the neck end of the cylindershown in FIGS. 6-8 with a piercable plug in the throat of the cylinder;

FIG. 10A is a top plan view of an embodiment of a piercable plug forplugging the throat of the cylinder shown in FIG. 9;

FIG. 10B is a partial cross-section of the pierceable plug as takenalong line 10B-10B in FIG. 10A;

FIG. 10C is an elevation view of the piercable plug of FIG. 10A shown inpartial cross-section;

FIG. 11 is a perspective view of the cylinder shown in FIGS. 6-10 with ahead valve installed on the neck of the cylinder;

FIG. 12A is a cross-sectional view of the head valve taken along line12A-12A in FIG. 11;

FIG. 12B is a cross-sectional view of the head valve taken along line12B-12B in FIG. 11;

FIG. 13 is a bottom perspective view of the head valve shown in FIGS.11-12B;

FIG. 14 is a perspective view of a two-stage motorless carbonating unitfor use in the system of FIG. 1 and the beverage dispensing module ofFIGS. 2-5;

FIG. 15 is a cross-sectional view of one of the carbonators of thetwo-stage carbonating unit shown in FIG. 14;

FIG. 16 is a perspective view of the front of an embodiment of aportable beverage dispensing cart according to the invention; and

FIG. 17 is a perspective view of the rear of the beverage dispensingcart shown in FIG. 16.

DETAILED DESCRIPTION

A schematic view of an embodiment of a compact and portable beveragedispensing system 10 according to the invention is shown in FIG. 1. Thesystem includes a source of compressed carbon dioxide (CO₂) gas 30, aflat water reservoir 20, a cold plate 50 with an ice tray 40, a waterpressure regulator 90, a first motorless carbonator 60, a secondmotorless carbonator 70, and a plurality of carbonated beverageflavorant supply reservoirs 130, and a plurality of non-carbonatedbeverage supply reservoirs 150. The system is capable of carbonatingflat water to between about 3.6 percent and about 4.2 percent CO₂ byweight without electricity or an external pressurized water supply.

The system provides two sequential stages of carbonation. Flat water isfirst carbonated to between about 2.4 percent and about 3.6 percent bythe first carbonator 60, and is then passed to the second carbonator 70where the soda from the first carbonator 60 is further carbonated up toabout 3.6 percent to about 4.2 percent. Thus, the system is capable ofsupplying soda with a carbonation level (by weight percent) that meetsor exceeds commercial standards for post-mixed beverages.

The system further includes a plurality of gas regulators 210, 220, 230;a pair of pneumatic water booster pumps 80, 100; a plurality ofcarbonated beverage flavorant supply pumps 140; a plurality ofnon-carbonated beverage supply pumps 160; a plurality of gas conduits300, 310, 320, 330, 340, 350, 360; a plurality of flat water conduits400, 410, 420, 430, 440; a plurality of soda conduits 500, 510, 520; anda plurality of flavorant conduits 600, 610. Flat water, soda, flavorantsfor carbonated beverages, and non-carbonated beverages are supplied to abar gun 120 for dispensing in a manner known in the art.

Compressed carbon dioxide (CO₂) gas is supplied to the system 10 from aCO₂ cylinder 30 through a CO₂ supply valve 35. In a preferredembodiment, the cylinder 30 is a disposable high-pressure cylinder 30capable of supplying compressed CO₂ at a pressure up to at least about1800 psi The supply valve permits and controls entry of CO₂ into thesystem 10 from the cylinder. A primary regulator 200 regulates thepressure of the CO₂ entering the system 10 from the cylinder 30 to about120 psi. Detailed descriptions of embodiments of the cylinder 30 andsupply valve 35 are discussed below

CO₂ from the cylinder 30 passes through three distinct conduit networkswithin the system 10. CO₂ is delivered through gas conduit 300 at apressure of about 120 psi to a first regulator 230 and a secondregulator 220. The first gas regulator 230 supplies CO₂ at about 83 psito the second water booster pump 100 via gas conduit 310. The second gasregulator 220 supplies CO₂ to the first carbonator 60 and the secondcarbonator 70 at about 100 psi through gas conduit 320. The second gasregulator 220 also supplies gas at about 100 psi to the third regulator210 through gas conduit 330. The third gas regulator 210 regulates thesupply of gas to the first water booster pump 80 via gas conduit 360,the non-carbonated beverage pumps 160 via gas conduits 350, and thecarbonated beverage flavorant pumps 140 via gas conduits 340 at about 56psi. The regulators preferably are adjustable in-line high pressure gasregulators such as those available from Ashby Industries.

The water booster pumps 80, 100 are pneumatic pumps powered bypressurized CO₂ gas. The water booster pumps 80, 100 pump flat water(uncarbonated) within the system 10 without electricity. The first andsecond water booster pumps 80, 100 may be FloJet® G Series pumps such asFloJet® Model G58 pumps, which are available from FloJet Corp. ofIrvine, CA. Other suitable pneumatic pumps may also be used in system10. The first water booster pump 80 draws flat water from the flat watersupply 20 through water conduit 400 and pumps the flat water to andthrough the cold plate 50. The flat water supply 20 may be a disposablebag. The cold plate 50 is chilled to about 32 degrees Fahrenheit by iceresiding in the ice tray 40. A drain 110 may be provided for drainingmelted ice from the ice tray 40 to a drain receptacle or bag 112. Theflat water is chilled in the cold plate 50 to about 33 degreesFahrenheit. A portion of the chilled water passes through conduit 420and to a water pressure regulator 90. Preferably, a water pressureregulator 90 is provided to regulate the pressure of the chilled flatwater passed to the second water booster pump 100 through water conduit430 to about 30 psig(?). The second water booster pump 100 pumps thechilled flat water to the first carbonator 60 at about 100 psi. Anotherportion of the chilled flat water exiting the cold plate 40 is divertedto the beverage dispensing gun 120 via water conduit 425.

Chilled flat water is subjected to a first stage of carbonation in thefirst carbonator 60. The solubility of gaseous CO₂ in water is maximizedwhen the water temperature is minimized and the pressure of the CO₂ gasto which the cold water is exposed is maximized. Because the flat wateris introduced into the first carbonator 60 at a temperature of about 33degrees Fahrenheit and the CO₂ gas is introduced into the firstcarbonator at a high pressure (about 100 psi), the carbonation of theflat water in the first carbonator is highly effective. In a preferredembodiment, the first carbonator 60 is capable of carbonating chilledflat water to between about 2.4 percent and about 3.6 percent. Thepressure of the CO₂ gas that is introduced into the first carbonator 60is limited by the pressure of the supplied flat water. If the gaspressure exceeds the water supply pressure, the flow of water into thecarbonator 60 will be inhibited by the excessive gas pressure.

The partially carbonated soda produced by the first carbonator 60 passesto the second carbonator through soda conduit 500 at a pressure of about100 psi. The second carbonator 70 further carbonates the partiallycarbonated soda to between about 3.6 percent and about 4.2 percent.Details of embodiments of the first and second carbonators 60, 70 arediscussed below. The fully carbonated soda produced by the secondcarbonator 70 is delivered to the cold plate 50 through soda conduit510. The fully carbonated soda is chilled to about 33 degrees Fahrenheitby the cold plate 50, and is passed to a soda dispensing gun 120 throughconduit 520 for post-mixing with carbonated beverage flavorants in amanner known in the art.

The system 10 includes one or more carbonated beverage flavorantsupplies 130. The carbonated beverage flavorant supplies 130 may bedisposable bags containing flavored syrups for soft drinks. The flavoredsyrup is drawn from each bag 130 through a syrup conduit 600 by adedicated pneumatic pump 140. The pneumatic pumps 140 may be FloJet®N5000 pumps, which are available from FloJet Corp. of Irvine,California, though other suitable pneumatic pumps may also be used. Thepumps 140 pump the syrups to a beverage dispensing gun 120 through syrupconduits 610.

The system 10 may also include supplies 150 of noncarbonated beveragesor noncarbonated beverage concentrates or flavorants. For example, thesupplies 150 may be disposable bags containing juices, juiceconcentrates, or fruit-flavored flavorants. When a supply 150 includes aconcentrate or flavorant, the concentrate or flavorant is post-mixedwith flat water at the dispensing gun 120. Each juice, juiceconcentrate, or other flavorant is drawn from its bag 150 by a dedicatedpump 150 through a conduit 700, and is delivered to the dispensing gun120 through a conduit 610.

The beverage dispensing gun 120 is of a type known in the art. Forexample, the beverage dispensing gun 120 may be an 8, 10, or 12-buttonWunder-Bar™ bar gun produced by Automatic Bar Controls, Inc. ofVacaville, California. Other suitable beverage dispensers or bar gunsmay also be used.

FIGS. 2-5 show one embodiment of a compact and portable beveragedispensing module 12 according to the invention. For clarity, theself-contained module 12 is shown in FIGS. 2-5 without the variousconduits that are indicated in FIG. 1. The various water, soda, gas, andsyrup conduits and their connections include suitably rated sanitarytubes and/or hoses and matching fittings like those known in the art.The module 12 includes a compact housing 240. Preferably, the housing isconstructed of aluminum. Various components of the module 12 arecontained within the housing 240. As shown in FIGS. 2-4, thehigh-pressure carbon dioxide cylinder 30 is positioned on the floor ofthe interior compartment 242 of the housing 240. As shown in FIGS. 2 and3, the supply valve 35 is mounted on the neck of the cylinder 30. Theprimary gas regulator 200, the first gas regulator 230, the second gasregulator 220, and the third gas regulator 210 are also mounted in thehousing 240. As best seen in FIGS. 4 and 5, the various pneumatic pumps80, 100, 140, and 160 are mounted on the sidewalls of the housing 240 bysuitable fasteners as best seen in FIGS. 4 and 5. A beverage-dispensingmanifold 125 is mounted on the roof of the housing, and distributeswater, soda, syrup, and/or juice to the bar gun 120 through a dispensingconduit 122.

FIGS. 6-8 show a disposable, compact high-pressure gas cylinder 30suitable for use in the beverage dispensing system 10 and the beveragedispensing module 12 is shown in FIGS. 6-8. The cylinder 30 includes abottom 38, a cylinder wall 32, a neck 33, and a throat 34. The neck 33includes external threads 37 for connecting the neck to the supply valve35. As shown in FIGS. 7 and 8, the throat 34 includes internal threads36, and a flat-bottomed counterbore 39. The cylinder 30 preferably isseamless, and is constructed of a suitable grade of aluminum, such as6061-T6 aluminum. In a preferred embodiment, the cylinder 30 is aDOT-3AL cylinder that is designed, constructed, and tested in accordancethe requirements of the U.S. Code of Federal Regulations, Title 49, Part178, Subpart C, Section 46 (37 CFR 178.46), entitled “Specification 3ALseamless aluminum cylinders”. Accordingly, a preferred aluminum cylinder30 is produced by the backward extrusion method. In addition, theminimum cylinder wall thickness is such that the wall stress at aminimum specified test pressure does not exceed eighty percent of theminimum yield strength of the cylinder material, and does not exceedsixty-seven percent of the minimum ultimate tensile strength of thematerial. Preferably, the cylinder 30 has a minimum service pressure of1800 psi and a minimum test pressure of 3000 psi. In a preferredembodiment, the cylinder has a nominal wall thickness of about 0.18inches, has a nominal outside diameter of about 4.34 inches, and has atotal length of about 12 inches. The cylinder 30 is disposable perDOT-39, and is not designed or intended to be recharged or reused. TheDOT-39 requirements for non-reusable (non-refillable) gas cylinders areidentified in the U.S. Code of Federal Regulations, Title 49, Part 178,Subpart C, Section 65 (37 CFR 178.65). In a preferred embodiment, thecylinder 30 has a water capacity between about 67.4 fluid ounces andabout 69 fluid ounces. The cylinder has a preferred maximum carbondioxide fill weight of about 3.0 pounds (or about 1361 grams).

As shown in FIG. 9, the throat 34 of cylinder 30 receives a piercableplug 42. As shown in FIGS. 10A and 10C, a preferred embodiment of thepiercable plug 42 includes a bushing 41 having a through bore 49, andexternal threads 48 for engagement with the internal threads 36 in thethroat 34. The plug 42 has a flat bottom 46 that seats in theflat-bottomed counterbore 39 of the cylinder 30, as shown in FIG. 12A.As shown in FIGS. 10A and 10B, the plug 42 may include a plurality ofspaced, one-way drive holes 43. As shown in FIG. 10B, each one-way drivehole 43 includes a vertical wall 43 a and an opposed sloped wall 43 b.To seat the plug 42 in the throat 34 of the cylinder 30, a suitablespanner wrench (not shown) can be engaged in the spaced drive holes 43to screw the plug 42 into the throat 34. The spanner wrench can be usedto apply circumferential forces to the vertical walls 43 a of the holes43 to apply a clockwise seating torque to the plug 42. Once the plug 42is seated in the cylinder 30, the sloped walls 43 b of the drive holes43 prevent the wrench from being used to apply a counterclockwise torqueto the plug 42 to loosen or remove the plug 42 from the cylinder 30.

As shown in FIGS. 10A and 10B, a frangible membrane 44 is centered inthe lower end of plug 42. The membrane 44 is captured on the end of thebushing 41 by a retainer 47 that is swaged on the end of the bushing asshown in FIG. 10C. The plug 42 is shown in FIG. 10A with the location ofa pierced hole 45 in the membrane 44 drawn in dashed lines. When themembrane 44 is pierced, the pierced hole 45 permits compressed gas topass through the membrane 44 and plug 42 and to exit the cylinder 30.The bushing 41 and retainer 47 preferably are constructed of brass. Thefrangible membrane 44 may be constructed of brass, gold, or any othermaterial that has sufficient strength to retain a compressed gas in thecylinder 30, and is also piercable. The plug 42 is configured to sealthe throat 34 of the cylinder 30 and to thereby seal pressurized carbondioxide within the cylinder 30 until the membrane 44 is pierced. Asuitable sealant or other seal may be used to form a pressure-resistantseal between the plug 42 and the throat 34 of the cylinder 30. Othertypes of high-pressure plugs also may be used as long as the plugs arecapable of containing high pressure gas within the cylinder and includea pierceable membrane 44.

FIGS. 11-13 show an embodiment of a supply valve 35. In FIGS. 11 and12A, the supply valve 35 is threaded onto the neck 33 of the cylinder30. The supply valve 35 preferably includes a one-piece body 52, a valvestem 54, an on-off actuator or plunger 58 that controls the exit of gasthrough an outlet port 56 a, and outlet fitting 56. The supply valve 35also includes a pair of overpressure rupture discs 51 and a pressuregauge 59 for indicating the pressure of gas in the cylinder 30. As shownin FIG. 12A, the valve stem 54 includes a pointed tip 57. The stem 54 isthreaded 55 in the valve body 52 such that the stem 54 can be insertedinto and withdrawn from the throat 34 of the cylinder by rotating thestem 54. To pierce the membrane 44 of the plug 42 and permit compressedgas to exit the cylinder 30, the stem 54 is rotated and advanced intothe throat 34 of cylinder 30 until the pointed tip 57 of the stem 54pierces the membrane 44 and forms an opening 45. The stem 34 is thenretracted from the throat 34 to permit gas to exit the cylinder 30through the opening 45 and enter the supply valve 35 through the piercedopening 45. When the plunger 58 is in a raised position, the outlet port56 a is closed, and gas is prevented from exiting the valve 35. When theplunger 28 is lowered, an exit path is opened and gas is permitted toexit the valve through outlet port 56 a. The high pressure carbondioxide from the cylinder 30 is then free to pass through a gas conduit300 to the first and second gas regulators 230, 220 as described above.One or more set screws 53 may be provided for selectively locking thestem 54 in a raised, non-piercing position to prevent inadvertentpiercing of the membrane 44 by the pointed tip 57.

FIG. 14 shows one embodiment of the first and second motorlesscarbonators 60, 70. Each carbonator 60, 70 includes a flat water inlet66, 76, a carbon dioxide inlet 62, 72, a soda outlet 64, 74, and apressure relief valve 68, 78. The first and second carbonators 60, 70may be connected together, by one or more brackets 79, for example Asindicated by the arrows in FIG. 14, chilled flat water enters the firstcarbonator 60 through water conduit 440 and water inlet 66. Preferably,the chilled flat water is supplied to the carbonator 60 at about 100 psiand about 33 degrees F. Carbon dioxide enters the carbonator 60 throughgas inlet 62 from gas conduit 320 at about 100 psi. In the carbonator60, a portion of the carbon dioxide gas is caused to dissolve in thechilled water, thereby producing partially carbonated soda with a CO₂content of about 2.4 to 3.6 percent. In one embodiment, the firstcarbonator 60 is capable of producing about 1.5 fluid ounces ofpartially carbonated soda per second.

The partially carbonated soda then passes from the first carbonator 60through outlet 64 and soda conduit 500, and enters the second carbonator70 through inlet 76 at about 100 psi. Carbon dioxide enters thecarbonator from gas conduit 320 at about 100 psi through gas inlet 72,and is caused to partially dissolve in the partially carbonated sodauntil carbonation reaches between about 3.6 and 4.2 percent. In oneembodiment, the second carbonator 70 is capable of producing about 1.5fluid ounces of fully carbonated soda per second. The fully carbonatedwater exits the second carbonator 70 through soda outlet 74, and ispassed to the cold plate of system 10 through soda conduit 510. Whensupplied with partially carbonated soda having about 2.4-3.6 percentcarbonation, the second carbonator is capable of producing fullycarbonated soda carbonated to about 3.6-4.2 percent. The second stage ofcarbonation ensures that the fully carbonated soda meets acceptablecommercial carbonation standards. Though the first and secondcarbonators 60, 70 are shown as separate components connected togetherby a bracket 79, persons of ordinary skill in the art will recognizethat a single component having first and second carbonation chambers mayalso be used.

FIG. 15 shows a cross section of one embodiment of a carbonation chamberor carbonator 60 for use in the two stage. An embodiment of the secondcarbonation chamber or carbonator 70 may be substantially the same asthe embodiment of the first carbonation chamber or carbonator 60 shownin FIG. 15. The carbonator 60 includes an enclosure 61 defining an innerchamber 63. A tube 69 is disposed in the chamber 63 and is connected tothe carbon dioxide inlet 62. A float 65 is disposed in the chamber 63and includes a pin or needle 67 that is slidably engaged in the tube 69.In the configuration shown in FIG. 15, the float 65 and needle 67 are ina lowermost position in the enclosure 61. In this position, the nose 67a of the needle 67 is seated in the tube 69 such that carbon dioxide gasis prevented from entering the inner volume 63 through the carbondioxide inlet 62. The float 65 has sufficient dry weight to hold thenose 67 a of the needle 67 in a seated position in the tube 69 inopposition to the pressure of the carbon dioxide trying to enter thecarbonator 60 through the gas inlet 62. The material of the float 65also has a density that is sufficiently low to cause the float 65 to bebuoyant in water. In a preferred arrangement, the enclosure 61, tube 69,and needle 67 are constructed of stainless steel, and the float 65 isconstructed of a food-grade Teflon®.

In operation, as carbonated soda is drawn from the carbonator 60 throughoutlet 64, the weight of the float 65 causes the float 65 and needle 67to fall to a closed position and to prevent pressurized gas fromcompletely backfilling the inner chamber 63 of the carbonator 60. Flatwater then enters the evacuated portion of chamber through water inlet66. As the flat water backfills the inner chamber 63 and reaches a levelin the enclosure 61 that is sufficient to cause the float 65 and needle67 to rise in the chamber 63, carbon dioxide is permitted to enter thechamber 63 through tube 69. Once an equilibrium is reached in thechamber 63, water and gas both are prevented from entering the chamber63. At the high pressure (about 100 psi) and low temperature (about 33degrees F.) within the chamber 63, the carbon dioxide gas is caused toat least partially dissolve in the flat water to form soda. In thetwo-stage carbonator shown in FIG. 14, partially carbonated soda exitsthe first carbonator 60 through soda outlet 64 and passes to the secondcarbonator 70 through soda inlet 76 for further carbonation.

FIGS. 16 and 17 show a portable beverage dispensing cart 800 thatincludes a beverage dispensing system 10 and beverage dispensing module12 as described above. The cart 800 includes a housing 802, an icechamber 812 with a movable cover 810, and a plurality of wheels orcasters 804. The cart 800 may include a first supply drawer 808 and asecond supply drawer 806. Preferably, one or both of the drawers 806 and808 include a lockable top for securing alcoholic beverages or the likeinside the drawers (not shown). In a preferred embodiment, the drawer806 is removable from the housing 802, and includes a channel-shaped lip807 that can be engaged on an edge 801 of the housing 802 to hang thedrawer 806 at a convenient position on the cart 800. A beveragedispensing gun 120 is positioned in the ice chamber 812. Ice placed inthe ice chamber rests atop and chills the cold plate 50 (see FIG. 1).The cold plate 50 forms the floor of the ice chamber 812 (not shown). Asink or basin may also be located inside the ice chamber for catchingspills and the like (not shown) As shown in FIGS. 16 and 17, the cart800 has a width “W”. Preferably, the width “W” is sufficiently narrow topermit the cart 800 to pass down the aisles of at least most commercialairliners. In a preferred embodiment, the cart is about 10-11 incheswide. Preferably, the cart complies with all applicable airline industrystandards for galley equipment.

Although only a few exemplary embodiments of this invention have beendescribed in detail above, those of ordinary skill in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of the appended claims. In theclaims, where a means-plus-function clause is recited, the clause isintended to cover the structures described herein as performing therecited function and not only structural equivalents, but alsoequivalent structures. Thus, although a nail and screw may not bestructural equivalents in that a nail employs a cylindrical surface tosecure wooden parts together, whereas a screw employs a helical surface,in the environment of fastening wooden parts, a nail and screw may beequivalent structures.

1. A portable beverage dispensing system comprising: (a) a supply offlat water: (b) a supply of pressurized gaseous carbon dioxide; (c) afirst motorless carbonator configured to receive a portion of the flatwater and a portion of the carbon dioxide and to cause a portion of thecarbon dioxide to dissolve in the flat water to produce partiallycarbonated soda; (d) a second motorless carbonator configured to receivea portion of the partially carbonated soda and a portion of the carbondioxide and to cause a portion of the carbon dioxide to dissolve in thepartially carbonated soda and to produce fully carbonated soda; (e) adispenser for selectively dispensing the fully carbonated soda; and (f)a flavored syrup supply and at least one pneumatic pump powered by thepressurized carbon dioxide, the pump being configured to cause flavoredsyrup to pass from the syrup supply to the dispenser, and wherein thedispenser mixes syrup with the fully carbonated soda in a desiredproportion.
 2. A portable beverage dispensing system according to claim1 wherein the flat water is supplied to the first motorless carbonatorat about 90 psi to about 110 psi.
 3. A portable beverage dispensingsystem according to claim 2 wherein the flat water is supplied to thefirst motorless carbonator at about 100 psi.
 4. A portable beveragedispensing system according to claim 1 wherein the carbon dioxide issupplied to the first and second motorless carbonators at about 90 psito about 110 psi.
 5. A portable beverage dispensing system according toclaim 4 wherein the carbon dioxide is supplied to the first and secondmotorless carbonators at about 100 psi.
 6. A portable beveragedispensing system according to claim 1 wherein the partially carbonatedsoda has about 2.4 percent to about 3.6 percent carbonation.
 7. Aportable beverage dispensing system according to claim 6 wherein thefully carbonated soda has about 3.6 percent to about 4.2 percentcarbonation.
 8. A portable beverage dispensing system according to claim1 and further including an ice-chilled cold plate, and wherein theportion of flat water received by the first carbonator is chilled by thecold plate before the flat water is received by the first carbonator. 9.A portable beverage dispensing system according to claim 8 wherein theportion of flat water received by the first carbonator is chilled by thecold plate to a temperature less than about 40 degrees Fahrenheit.
 10. Aportable beverage dispensing system according to claim 8 wherein theportion of flat water received by the first carbonator is chilled by thecold plate to a temperature of about 33 degrees Fahrenheit.
 11. Aportable beverage dispensing system according to claim 1 wherein thesupply of pressurized gaseous carbon dioxide comprises a high pressuregas cylinder, and the cylinder conforms to the requirements of 49 CFR178.46.
 12. A portable beverage dispensing system according to claim 1wherein the supply of pressurized gaseous carbon dioxide comprises ahigh pressure gas cylinder, and the cylinder has a liquid capacity ofabout 68 fluid ounces.
 13. A portable beverage dispensing systemaccording to claim 1, wherein the supply of pressurized gaseous carbondioxide comprises a high pressure gas cylinder having a neck with athroat, and a plug inserted and retained within the throat and having apiercable membrane connected thereto, and further comprising a gassupply valve having a stem configured for selectively piercing themembrane.
 14. A portable beverage dispensing system according to claim 1and further comprising at least one pneumatic pump powered by thepressurized carbon dioxide, the pump being configured to cause flatwater to pass from the water supply to the first carbonator.
 15. Aportable beverage dispensing system comprising: (a) a supply of flatwater; (b) a high pressure cylinder containing pressurized carbondioxide and including a neck having a throat and a selectively piercablemembrane sealing the throat; (b) at least one motorless carbonatorconfigured to receive a portion of the flat water and a portion of thecarbon dioxide and to cause a portion of the carbon dioxide to dissolvein the flat water to produce carbonated soda; (c) a dispenser forselectively dispensing carbonated soda and (d) a flavored syrup supplyand at least one pneumatic pump powered by the pressurized carbondioxide the pump being configured to cause flavored syrup to pass fromthe syrup supply to the dispenser, and wherein the dispenser mixes syrupwith the carbonated soda in a desired proportion.
 16. A portablebeverage dispensing system according to claim 15 and comprising; (a) afirst motorless carbonator configured to receive a portion of the flatwater and a portion of the carbon dioxide and to cause a portion of thecarbon dioxide to dissolve in the flat water to produce partiallycarbonated soda; (d) a second motorless carbonator configured to receivea portion of the partially carbonated soda and a portion of the carbondioxide and to cause a portion of the carbon dioxide to dissolve in thepartially carbonated soda and to produce fully carbonated soda.
 17. Aportable beverage dispensing system according to claim 15 wherein theflat water is supplied to the carbonator at about 90 psi to about 110psi.
 18. A portable beverage dispensing system according to claim 17wherein the flat water is supplied to the first motorless carbonator atabout 100 psi.
 19. A portable beverage dispensing system according toclaim 15 wherein the carbon dioxide is supplied to the carbonator atabout 90 psi to about 110 psi.
 20. A portable beverage dispensing systemaccording to claim 19 wherein the carbon dioxide is supplied to thecarbonator at about 100 psi.
 21. A portable beverage dispensing systemaccording to claim 15 wherein the carbonated soda has about 2.4 percentto about 4.2 percent carbonation.
 22. A portable beverage dispensingsystem according to claim 15 and further including an ice-chilled coldplate, and wherein the portion of flat water received by the carbonatoris chilled by the cold plate before the flat water is received by thecarbonator.
 23. A portable beverage dispensing system according to claim22 wherein the portion of flat water received by the carbonator ischilled by the cold plate to a temperature less than about 40 degreesFahrenheit.
 24. A portable beverage dispensing system according to claim22 wherein the portion of flat water received by the carbonator ischilled by the cold plate to a temperature of about 33 degreesFahrenheit.
 25. A portable beverage dispensing system according to claim15 wherein the membrane is configured to resist rupture at pressuresless than or equal to about 1800 psi.
 26. A portable beverage dispensingsystem according to claim 15 wherein the cylinder conforms to therequirements of 49 CFR 178.46.
 27. A portable beverage dispensing systemaccording to claim 15 wherein the cylinder has a liquid capacity ofabout 68 fluid ounces.
 28. A portable beverage dispensing systemaccording to claim 15 and further comprising a gas supply valve having astem configured for selectively piercing the membrane.
 29. A portablebeverage dispensing system according to claim 15 and further comprisingat least one pneumatic pump powered by the pressurized carbon dioxide,the pump being configured to cause flat water to pass from the watersupply to the carbonator.
 30. A portable beverage dispensing module, themodule comprising: (a) a housing; (b) a supply of pressurized gaseouscarbon dioxide (c) a first motorless carbonator in the housing, thefirst carbonator being configured to receive flat water from a flatwater supply and to receive a portion of the carbon dioxide, and tocause a portion of the carbon dioxide to dissolve in the flat water toproduce partially carbonated soda; (d) a second motorless carbonator inthe housing, the second carbonator being configured to receive thepartially carbonated soda and a portion of the carbon dioxide and tocause a portion of the carbon dioxide to dissolve in the partiallycarbonated soda and to produce fully carbonated soda; (e) a dispenserfor selectively dispensing the fully carbonated soda; and (d) at leastone pneumatic pump powered by the pressurized carbon dioxide, the pumpbeing configured to cause flavored syrup to pass from a syrup supply tothe dispenser, and wherein the dispenser mixes syrup with the fullycarbonated soda in a desired proportion.
 31. A portable beveragedispensing module according to claim 30 wherein the carbon dioxide issupplied to the first and second motorless carbonators at about 90 psito about 110 psi.
 32. A portable beverage dispensing module according toclaim 30 wherein the carbon dioxide is supplied to the first and secondmotorless carbonators at about 100 psi.
 33. A portable beveragedispensing module according to claim 30 wherein the partially carbonatedsoda has about 2.4 percent to about 3.6 percent carbonation.
 34. Aportable beverage dispensing module according to claim 30 wherein thefully carbonated soda has about 3.6 percent to about 4.2 percentcarbonation.
 35. A portable beverage dispensing module according toclaim 30 and further including an ice-chilled cold plate, and whereinthe portion of flat water received by the first carbonator is chilled bythe cold plate before the flat water is received by the firstcarbonator.
 36. A portable beverage dispensing module according to claim35 wherein the portion of flat water received by the first carbonator ischilled by the cold plate to a temperature less than about 40 degreesFahrenheit.
 37. A portable beverage dispensing module according to claim35 wherein the portion of flat water received by the first carbonator ischilled by the cold plate to a temperature of about 33 degreesFahrenheit.
 38. A portable beverage dispensing module according to claim30 wherein the membrane is configured to resist rupture at pressuresless than or equal to about 1800 psi.
 39. A portable beverage dispensingmodule according to claim 30 wherein the cylinder conforms to therequirements of 49 CFR 178.46.
 40. A portable beverage dispensing systemaccording to claim 30 wherein the cylinder has a liquid capacity ofabout 68 fluid ounces.
 41. A portable beverage dispensing moduleaccording to claim 30 and further comprising a gas supply valve having astem configured to selectively pierce the membrane.
 42. A portablebeverage dispensing module, the module comprising: (a) a housing; (b) ahigh pressure cylinder in the housing, the cylinder containingpressurized carbon dioxide and including a neck having a throat and aselectively piercable membrane sealing the throat; (c) at least onemotorless carbonator in the housing, the carbonator being configured toreceive flat water from a flat water supply and a portion of the carbondioxide and to cause a portion of the carbon dioxide to dissolve in theflat water to produce carbonated soda; (e) a dispenser for selectivelydispensing the carbonated soda, and; (f) a flavored syrup supply and atleast one pneumatic pump powered by the pressurized carbon dioxide, thepump being configured to cause flavored syrup to pass from the syrupsupply to the dispenser and wherein the dispenser mixes syrup with thecarbonated soda in a desired proportion.
 43. A portable beveragedispensing module according to claim 42, the module comprising: (a) afirst motorless carbonator in the housing, the first carbonator beingconfigured to receive flat water from a flat water supply and to receivea portion of the carbon dioxide, and to cause a portion of the carbondioxide to dissolve in the flat water to produce partially carbonatedsoda; and (b) a second motorless carbonator in the housing, the secondcarbonator being configured to receive the partially carbonated soda anda portion of the carbon dioxide and to cause a portion of the carbondioxide to dissolve in the partially carbonated soda and to producefully carbonated soda; and (c) a dispenser for selectively dispensingthe fully carbonated soda.
 44. A portable beverage dispensing moduleaccording to claim 42 wherein the flat water is supplied to thecarbonator at about 90 psi to about 110 psi.
 45. A portable beveragedispensing module according to claim 42 wherein the flat water issupplied to the carbonator at about 100 psi.
 46. A portable beveragedispensing module according to claim 42 wherein the carbon dioxide issupplied to the carbonator at about 90 psi to about 110 psi.
 47. Aportable beverage dispensing module according to claim 42 wherein thecarbon dioxide is supplied to the carbonator at about 100 psi.
 48. Aportable beverage dispensing module according to claim 42 wherein thecarbonated soda has about 2.4 percent to about 4.2 percent carbonation.49. A portable beverage dispensing module according to claim 42 andfurther including an ice-chilled cold plate, and wherein the flat waterreceived by the carbonator is chilled by the cold plate before the flatwater is received by the carbonator.
 50. A portable beverage dispensingmodule according to claim 42 wherein the flat water received by thecarbonator is chilled by the cold plate to a temperature less than about40 degrees Fahrenheit.
 51. A portable beverage dispensing moduleaccording to claim 42 wherein the flat water received by the carbonatoris chilled by the cold plate to a temperature of about 33 degreesFahrenheit.
 52. A portable beverage dispensing module according to claim42 wherein the membrane is configured to resist rupture at pressuresless than or equal to about 1800 psi.
 53. A portable beverage dispensingmodule according to claim 42 wherein the cylinder conforms to therequirements of 49 CFR 178.46.
 54. A portable beverage dispensing moduleaccording to claim 42 wherein the cylinder has a liquid capacity ofabout 68 fluid ounces.
 55. A portable beverage dispensing moduleaccording to claim 42 and further comprising a gas supply valve having astem configured for selectively piercing the membrane.
 56. A portablebeverage dispensing module according to claim 42 and further comprisingat least one pneumatic pump powered by the pressurized carbon dioxide,the pump being configured to cause flat water to pass from a watersupply to the carbonator.